Field of the Invention
One disclosed aspect of the embodiments relates to a solid-state imaging device and a method of manufacturing the same.
Description of the Related Art
In recent years, the reduction in the size of a single pixel has been accelerated with the increase in the number of pixels included in a single solid-state imaging device. In such a solid-state imaging device, a reduction in the size of the pixel may lead to a reduction in the area of a light-receiving surface of a photoelectric conversion portion and then to a reduction in the sensitivity of the photoelectric conversion portion. To suppress such a reduction in the sensitivity, a configuration is disclosed by Japanese Patent Laid-Open No. 11-40787 in which an inner lens is provided between a photoelectric conversion portion and an on-chip lens. According to Japanese Patent Laid-Open No. 11-40787, the inner lens is formed from a silicon nitride film or a silicon oxynitride film.
According to Japanese Patent Laid-Open No. 11-40787, relevant elements such as charge-transfer portions and wiring layers are formed on a substrate, a transparent film made of a material such as silicon nitride or silicon oxynitride is formed thereon by plasma chemical-vapor deposition (CVD), and a resist layer is formed thereon by applying a resist thereto. Subsequently, the resist layer is patterned and is subjected to reflowing, and the transparent film is etched by using the resist pattern as a mask, whereby inner lenses are formed. In such a manufacturing method, the resist layer formed on the transparent film tends to be patterned by using a mask positioned with reference to a pattern formed at a position that is nearer to the substrate than the transparent film is.
In the process disclosed by Japanese Patent Laid-Open No. 11-40787, a stress occurring in the transparent film may distort the substrate. In such an event, the predetermined pattern and the mask may be misaligned with each other. Consequently, the inner lenses formed by patterning the transparent film may be displaced from respective desired positions, resulting in failure in providing a highly reliable solid-state imaging device.